Precision engineering of high-performance Ni-rich layered cathodes with radially aligned microstructure through architectural regulation of precursors

Abstract

Microstructure engineering serves as a potent approach to counteract the mechanical deterioration of Ni-rich layered cathodes, stemming from anisotropic strain during Li⁺ (de)intercalation. However, a pressing challenge persists in devising a direct method for fabricating radially aligned cathodes utilizing oriented hydroxide precursors. In this study, we synthesized LiNi_0.92Co_0.04Mn_0.04O₂ oxides boasting superior radially aligned, size-refined primary particles through a combination of strategic precipitation regulation and lithiation tuning. Elongated primary particles, achieved by stepwise control of ammonia concentration and pH during particle growth, facilitate the formation of radially aligned hydroxide precursor particles. Leveraging the size-refined and radially aligned primary particles, our prepared LiNi_0.92Co_0.04Mn_0.04O₂ cathode exhibits a high discharge capacity of 229 ​mAh ​g⁻¹ ​at 0.05 C, alongside excellent cycle stability, retaining 93.3% capacity after 200 cycles at 0.5 C (30 ​°C) in a half cell, and 86.4% capacity after 1000 cycles at 1 C (30 ​°C) in a full cell. Revisiting the regulation from precursor to oxide underscores the significance of controlling primary particles to maximize size perpendicular to [001] and attain suitable size along [001] during precursor precipitation and high-temperature calcination, offering valuable insights for synthesizing high-performance Ni-rich cathodes.